A303633 Number of nX5 0..1 arrays with every element unequal to 2 or 3 horizontally or vertically adjacent elements, with upper left element zero.

0, 3, 0, 8, 20, 66, 207, 726, 2461, 8538, 29072, 100909, 345464, 1192462, 4104543, 14145598, 48741105, 167919091, 578641035, 1993746222, 6869984946, 23672540436, 81569450595, 281073069448, 968513250894, 3337304064491, 11499656306463

Offset

1,2

Comments

Column 5 of A303636.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 4*a(n-1) +3*a(n-2) -21*a(n-3) +15*a(n-4) +20*a(n-5) -113*a(n-6) +119*a(n-7) +47*a(n-8) -605*a(n-9) +1543*a(n-10) -410*a(n-11) -2330*a(n-12) +4699*a(n-13) -5222*a(n-14) +1426*a(n-15) +6743*a(n-16) -13402*a(n-17) +8575*a(n-18) +2680*a(n-19) -11720*a(n-20) -5652*a(n-21) +5363*a(n-22) +16884*a(n-23) -3961*a(n-24) +3927*a(n-25) +1752*a(n-26) -7869*a(n-27) +2055*a(n-28) +872*a(n-29) -2059*a(n-30) +338*a(n-31) +346*a(n-32) -322*a(n-33) +74*a(n-34) +159*a(n-35) -165*a(n-36) +47*a(n-37) +15*a(n-38) -6*a(n-39)

Example

Some solutions for n=5
..0..1..0..1..0. .0..1..1..0..1. .0..1..0..1..0. .0..1..0..1..0
..1..1..0..0..1. .1..0..0..1..0. .1..1..0..1..1. .1..0..0..1..1
..0..0..1..1..0. .0..1..0..1..1. .0..0..1..0..0. .0..1..1..0..0
..1..0..1..1..0. .0..1..1..0..0. .1..0..1..0..1. .1..0..0..1..1
..0..1..0..0..1. .1..0..1..0..1. .0..1..0..1..0. .0..1..0..1..0

Crossrefs

Cf. A303636.

Sequence in context: A019691 A192919 A068607 * A167004 A287632 A259346

Adjacent sequences: A303630 A303631 A303632 * A303634 A303635 A303636

Keyword

nonn

Author

R. H. Hardin, Apr 27 2018

Status

approved